“No,” said Tubby.
“It is like air. But you cannot breathe it. It exists everywhere—even in the outermost realms of Space. Now do you understand?”
“Yes,” said Tubby.
“Light is vibration of the Ether,” the professor went on in his droning voice. “Its vibrations travel through the Ether at the rate of one hundred and eighty-six thousand three hundred and twenty-four miles a second.”
“I know that,” said Tubby.
“You are a learned man,” the professor said admiringly. “You have a wonderful mind. I knew you had—they said so.”
“Yes,” said Tubby. “Go on.”
The professor jerked his little body upright in his chair suddenly, so suddenly that Tubby started violently with fright.
“How long is a second?” the professor asked aggressively.
“Why—tick-tick. That’s it,” said Tubby.